OAKLAND, Calif. -- The Oakland Athletics lowered their magic number to one for clinching their second straight AL West title, beating the Minnesota Twins 9-1 Saturday behind the pitching of Jarrod Parker and hitting of Alberto Callaspo.

The A’s have won 12 of 15 and are 16 of their last 21, opening a season-high 7½-game lead over second-place Texas entering Saturday. Texas was Kansas City later in the day.

Oakland players filed quietly off the field to a standing ovation from the Oakland Coliseum crowd after reliever Jerry Blevins got the final out.

Parker (12-7), who may start the A’s postseason opener, gave up one run and four hits in six innings, allowed only two runners past first and didn’t walk a batter for the fifth time this season. He gave up eight runs against the Los Angeles Angels on Sept. 16.

Callaspo matched his career highs with four hits and had three RBIs. Kurt Suzuki and Yoenis Cespedes homered for the A’s, and Jed Lowrie had three hits.

The game started after a two-hour rain delay. The visiting dugout was flooded and sewage backed up in the A’s coaches’ bathroom, the third such incident at the Coliseum this season. The infield was covered by a silver tarp before the game and workers repeatedly had to sweep big puddles of water away.

Josmil Pinto homered for Minnesota, 1-5 on its trip. Twins starter Pedro Hernandez (3-2) gave up six runs and eight hits in two innings.

Callaspo’s two-out single in the first drove in Lowrie, and the A’s opened a 6-0 lead with a five-run second. Chris Young had a sacrifice fly, Cespedes a two-run single and Callaspo a two-run homer.

Suzuki added a two-run homer in the sixth off Liam Hendricks and Cespedes hit 26th homer in the eighth.

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